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[StorageSystem] SSD
September 6, 2018

[StorageSystem] SSD

Write Amplification in SSD We need to have a map betwwen LBA to PBA, logical block address to physical block address. In DRAM, overwrite/ update would be relatively easy, find the address, and then replace the old value with the new value directly. But it …

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Leetcode 76 Minimum Window Substring 最小窗口子串
September 5, 2018

Leetcode 76 Minimum Window Substring 最小窗口子串

Given a string S and a string T, find the minimum window in S which will contain all the characters in T in complexity O(n). Example: Input: S = “ADOBECODEBANC”, T = “ABC” Output: “BANC” Note: If there is no such window in S that …

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[DatabaseSystem] Database Storage 1
September 5, 2018

[DatabaseSystem] Database Storage 1

Today we would focus on how data organized in disk. DBMS would assume that the primary storage is lied on the non-volatile storage. Storage Hierarchy Overview Typical Storage Layer: cpu register cpu cache DRAM (Non-volitile memory) SSD HDD Network Storage Usually data is moved from …

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【纪行】有些尴尬
September 5, 2018

【纪行】有些尴尬

interview session的开场白是一段对雅虎大公司病的十分钟批判，听得台下的我如坐针毡。虽然说我很多时候也不看好我司，但是大庭广众下被其他人指着骂也多半是令人不快的，而且还是被人当段子来衬托自己的startup。

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【纪行】权当颓唐无力的碎碎念了
September 3, 2018

【纪行】权当颓唐无力的碎碎念了

近来找工作很勤，然而越是找下去，就越是有一种无力感。上个月databricks onsite之后，感觉信心和士气都泄了；之后一个月里面一方面主观上不太有信心和动力继续找下去，另一方面客观上也没有什么实质性的进展，一僵持就到今天了。

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[Storage System] High Level Overview and Perofrmance Metrics
September 3, 2018

[Storage System] High Level Overview and Perofrmance Metrics

Software (file systems, device drivers, firmware) and Hardware (servers, devices, controllers, interconnect) that collectively provide application writers with an infrastructure that retains persistent data and provides it on request

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[DatabaseSystem] Advanced SQL
September 1, 2018

[DatabaseSystem] Advanced SQL

SQL is a kinf of relational languages, in which users only need to specify the answer that they want, not how to compute it. The DBMS is reponsible for efficient evaluate and optimize the query.

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[DatabaseSystem] Database Introduction And Relational Model
September 1, 2018

[DatabaseSystem] Database Introduction And Relational Model

Database System is an organized collection of inter-related data that models some aspect of the real-world. Databases are core of most computer applications. Before the whole course discussion, first question is that why we need database system.

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